To a mixture of 2-(4-{[tert-Butoxycarbonyl-(3-tert-butoxycarbonylamino-propyl)-amino]-methyl}-phenyl)-3-methoxy-acrylic acid methyl ester (5.70 g, 11.92 mmol), 5-(4-bromo-phenyl)-1H-imidazol-2-ylamine (2.84 g, 11.92 mmol) and ethanol (60 mL) was added a solution of sodium methoxide (12 mL, 0.5 M in methanol, 6 mmol). The resulted mixture was refluxed for 18 h, additional 12 mL of sodium methoxide (0.5 M in methanol, 6 mmol) was added and continued to reflex for 20 h. The reaction was concentrated and diluted with EtOAc (300 mL) and washed with water (200 mL), brine (200 mL). The EtOAc solution was concentrated. The crude product was purified by flash chromatography (0%-8% Methanol in dichloromethane) to give desired product (4.05 g, 52%) as brown solid. 1NMR (300 MHz, CDCl3): δ 7.96 (s, 1H), 7.68 (d, J=8.1 Hz, 2H), 7.54 (m, 2H), 7.35(s, 1H), 7.27 (d, J=8.1 Hz, 2H), 5.25 (br.s, 0.5H), 4.70 (br.s, 0.5H), 4.44 (s, 2H), 3.29 (m, 2H), 3.11 (m, 2H), 1.67 (m, 2H), 1.52 (br.d, 9H), 1.44 (s, 9H). LCMS (EI) m/z: 654 (M+H+).
